RESUMO
This study evaluated the effects of phytase supplementation on growth performance and apparent digestibility of Nile tilapia (Oreochromis niloticus) in a commercial fish farm setting. Nile tilapia (6300 male, 57.48 ± 1.04 g) were randomly stocked into 42 floating cages. The experimental design was completely randomized, comprising six treatments and seven replications. Fish were fed five phosphorus deficient plant-based diets with graded levels of phytase supplementation (0, 500, 1000, 1500, 2000 UF kg-1) and an additional diet containing phosphorus supplementation to meet the requirement of this fish species (positive control). After 97 days of feeding, growth performance data were collected and 900 fish (500 ± 10 g) were relocated to 6 floating cages for the digestibility assessment. Quadratic polynomial regression analysis indicated 1537.5 and 1593.2 UF kg-1 as the optimum dietary levels for daily weight gain and feed conversion rate, respectively. Including 2000 UF kg-1 resulted in the higher dry matter, crude protein, energy, and ash apparent digestibility coefficient values. Therefore, phytase supplementation from 1500 to 2000 UF kg-1 is recommended to enhance growth performance and nutrient bioavailability of Nile tilapia reared according to industry practices.
RESUMO
Este estudo foi realizado com o objetivo de avaliar o desempenho produtivo da tilápia do Nilo (Oreochromis niloticus) alimentada com níveis de colina na dieta pelo período de 109 dias. Foram utilizados 192 alevinos com 4,0 ± 0,15 g de peso médio, distribuídos em 32 tanques-rede de 200 L, na densidade de seis peixes por tanque-rede, dispostos em aquários de 1.000 L. O delineamento experimental foi inteiramente casualizado com oito tratamentos e quatro repetições. As rações foram suplementadas com 0, 100, 200, 400, 600, 800, 1.000 e 1.200 mg de colina kg-1 de ração. Não foram observadas diferenças para ganho de peso, taxa de sobrevivência, conversão alimentar aparente, porcentagem de extrato etéreo do filé e do fígado, índice hepatossomático e concentração de lipídeos no plasma. Concluiuse que os diferentes níveis de colina não melhoraram o desempenho produtivo dos peixes nestas condições, pois a dieta basal supostamente supriu a exigência do peixe para colina.(AU)
A 109-day feeding trial was undertaken aiming to evaluate the growth performance of Nile tilapia fed graded choline levels. One hundred and ninety-two (initial weight 4.0 ± 0.15 g) fingerlings were distributed into 32 net cages (200 L each), four cages per treatment and six fish per cage, placed in eight 1000L aquaria in a closed recirculation system. The treatments were assigned to the tanks comprising eight treatments and four replications arranged in a completely randomized experimental design. Diets were supplemented with choline chloride to provide 100, 200, 400, 600, 800, 1000, 1200 mg of choline per kg of feed and an unsupplemented diet. No significant differences were observed in growth performance, survival, apparent feed conversion, liver and fillet ether extract, hepatosomatic index and plasma lipid concentration, among treatments. Choline levels did not improve growth performance, possibly because the amount of choline in the diet had already met fish requirement.(AU)
Assuntos
Animais , Colina , CiclídeosRESUMO
Este estudo foi realizado com o objetivo de avaliar o desempenho produtivo da tilápia do Nilo (Oreochromis niloticus) alimentada com níveis de colina na dieta pelo período de 109 dias. Foram utilizados 192 alevinos com 4,0 ± 0,15 g de peso médio, distribuídos em 32 tanques-rede de 200 L, na densidade de seis peixes por tanque-rede, dispostos em aquários de 1.000 L. O delineamento experimental foi inteiramente casualizado com oito tratamentos e quatro repetições. As rações foram suplementadas com 0, 100, 200, 400, 600, 800, 1.000 e 1.200 mg de colina kg-1 de ração. Não foram observadas diferenças para ganho de peso, taxa de sobrevivência, conversão alimentar aparente, porcentagem de extrato etéreo do filé e do fígado, índice hepatossomático e concentração de lipídeos no plasma. Concluiuse que os diferentes níveis de colina não melhoraram o desempenho produtivo dos peixes nestas condições, pois a dieta basal supostamente supriu a exigência do peixe para colina.
A 109-day feeding trial was undertaken aiming to evaluate the growth performance of Nile tilapia fed graded choline levels. One hundred and ninety-two (initial weight 4.0 ± 0.15 g) fingerlings were distributed into 32 net cages (200 L each), four cages per treatment and six fish per cage, placed in eight 1000L aquaria in a closed recirculation system. The treatments were assigned to the tanks comprising eight treatments and four replications arranged in a completely randomized experimental design. Diets were supplemented with choline chloride to provide 100, 200, 400, 600, 800, 1000, 1200 mg of choline per kg of feed and an unsupplemented diet. No significant differences were observed in growth performance, survival, apparent feed conversion, liver and fillet ether extract, hepatosomatic index and plasma lipid concentration, among treatments. Choline levels did not improve growth performance, possibly because the amount of choline in the diet had already met fish requirement.